The present invention relates to a wide-view endoscope compatible with high definition television (xe2x80x9cHDTVxe2x80x9d) format. More particularly, the present invention relates to a HDTV compatible endoscope for use in minimally invasive surgical procedures.
Traditionally endoscopes were of the rigid xe2x80x9crod-lensxe2x80x9d type, utilizing a series of lenses to relay the image of an object from a distal end to a proximal eyepiece or other viewing means. Such a device is taught in U.S. Pat. No. 4,168,882, whose disclosure is incorporated herein by reference. In that device, the image of an object area is formed by a first distal lens. A second lens re-images the first image to a third lens, which re-images the second image to a fourth lens, and so on, until the image is relayed to the viewing means. Such devices are generally plagued by the need for repeated maintenance and poor maneuverability.
The use of fiber optic, multifilament and optical fiber bundles, in connection with the transmission of image light is well known in the art. The inclusion of such optics in an endoscope capable of transmitting a sufficient quantity of light to the dark field of vision is disclosed, and incorporated herein by reference, in U.S. Pat. No. 4,872,740. This endoscope, while providing greater maneuverability, and lower maintenance, is very expensive and provides limited picture quality.
An improved endoscope, for remotely examining cavities, utilizing a solid transparent high refractive index tunnel rod, in place of the conventional series of lenses, for conducting image light from a distal end to a proximal end of the device is taught, and incorporated herein by reference, in U.S. Pat. No. 5,630,784. In that device, an enhanced image is provided in a more costly manner through minimizing veiling glare and reducing contrast of the image through the development and inclusion of a high refractive index tunnel rod. This tunnel rod both shortens the apparent distance from the proximal to the distal end by virtue of its refractive index being greater than that of air, and provides a light tunnel which can transmit image light over a relatively long distance without veiling energy from wallscatter or by virtue of its lightly refractive inside walls. Despite this great leap forward, surgeons, particularly those involved in minimally invasive and endoscopic procedures are faced with the dilemma of operating on three-dimensional patients while viewing standard two-dimensional images on their monitor. They are deprived under such circumstances from the benefits of depth perception, as well as from the opportunity to effectively differentiate the targeted organs and tissue from their surroundings.
In addition, as depicted in FIGS. 2 and 3, traditional endoscopes, when used in combination with monitors, either increase magnification to oversize the image, or increase the optic field size by decreasing magnification. In either case, the Surgeon""s view suffers through either a reduction of her optic field or increased vignetting, respectively. These quandaries are exacerbated when traditional endoscopes are combined with HDTV cameras, since HDTV provides, in addition to greater resolution, a wider format through an aspect ratio of 16:9. Further, as provided above, traditional endoscopes are neither efficient in the use of the entire optical path, nor capable of providing sufficient imaging to leverage the benefits provided through utilizing the HDTV equipment and format.
Therefor, it is an object of the present invention to provide an improved endoscope that provides a sharper, more focused picture having a wider field of view, while providing enhanced depth perception, without generating vignetting.
It is a further object of the present invention to provide a wide-view endoscope that incorporates a HDTV camera and is compatible with HDTV format. By using the same aspect ratio as the HDTV camera and HDTV imager, the present invention will transmit the entire optical path thus filling the full screen and providing the surgeon with an increased optical field. In addition, the HDTV format will greatly improve resolution, and ensure that the surgeon will have sufficient picture definition to delineate fine details and shadowing.
It is still a further object of the present invention to provide surgeons an effective and useful means of performing minimally invasive and endoscopic procedures previously prevented as a result of the limited resolution, poor maneuverability and the generation of vignetting by prior art endoscopes.
The present invention is directed to a wide-view endoscope that incorporates a HDTV camera and is HDTV compatible. This invention combines rectangular shaped lens elements and a differential light source. The rectangular shaped lens elements ensure that the lens pathway is fully mapped to wide format image detector of the HDTV camera. The sides of the lens elements are coated or blackened to limit glare and refractive errors. Further, the rectangular lens elements naturally form asymmetric gaps, which surround the lens element and provide a pathway for inclusion of the illuminating conduits, within the generally round endoscope body. The overall affect achieved through this orientation, is the maximization of the optical conduit by matching the shape of the lens package to that of the detector (HDTV camera chip), without increasing the outside diameter of the endoscope.
Shadowing is produced through the placement of the illuminating conduits in a non-concentric orientation. With the higher resolution and increased signal bandwidth achievable with a HDTV camera, the object shadowing will provide enhanced depth perception. This is particularly advantageous, in minimally invasive procedures, since the surgeon will gain a significantly better view of the surface she is working on, while requiring less space through the reduced diameter of the present invention. In turn, this will facilitate the surgeon""s maneuvering of her instruments or the endoscope in a smaller space then traditionally required with such minimally invasive procedures, while permitting her to access and view tissues which traditional endoscopes could not reach.